They were telling people to drive away from the storm. Usually, that's horrible advice because the path of a tornado isn't predictable. In this case, I think the weather service realized going in that this might be in the F4 F5 category and above ground structures cannot handle that. It was good advice in that particular situation if you were in a house without underground shelter. Usually, you do NOT want to be in a car when a tornado is on the ground. So - 9 times out of ten, do not try to drive away from a tornado.
In fact, in the last two major tornadoes with death tolls, a lot of the people killed were in their cars.
Driving away is actually pretty good advice
if you understand that these storms generally track Northeast AND you understand which direction to drive. If the tornado is many miles to your West, driving straight South is the best bet to avoid it. You don't want to wind up driving toward it, or trying to outrun it in the direction it's headed unless you can actually SEE it. And, you must keep up to date on other spin offs from the same storm.
My wife & I had a scary situation in MS one time. We were listening to the local radio station in our car & they broke in to say a tornado had been spotted 5 miles West of Union, MS (not positive that was the name of the town). Well, we had no idea where in MS that was until JUST THEN when we passed a sign that said, "Union, MS 5 miles"
So, now we're in a pickle - do we stop and hope it passes us to the North, or do we try to outrun it? If we hadn't been on the Interstate, we'd have turned around & gone back South, but there was no place to turn around. Then, we spotted a sign for a rest stop, but when we got there, the only "structures" were port-a-potties
We eventually rode it out, but it got ugly. We believe we missed it just to the South though we did run into severe hail, wind, and rain. After it cleared, we came upon a car 100 yards off the road wrapped around a tree with a sheet over it. Was a car that had passed us a few miles earlier
We decided that having an awareness of where we are on the road could be a life saver.